Cable tie

Abstract

An improved cable tie having elongated generally semi-cylindrical beads longitudinally interconnecting the rack teeth on the cable tie strap so as to increase the material thickness adjacent a portion of the root sections of the rack teeth and to form an elongation of the transverse stress line and diversion thereof in a non-linear direction to increase the fracture resistance of the strap adjacent the rack teeth root sections where the strap has its minimum material thickness.

I claim as my invention: 
     
       1. A cable tie comprising in combination, a head and an elongated integrally connected strap terminating in a tail, said head having an opening for progressive insertion of said tail and strap,   said strap being formed with elongated side rails defining a longitudinally extending channel having a channel floor,   said channel containing a rack formed of a plurality of successive, longitudinally spaced, transversely extending rack teeth each having a portion merging integrally into said channel floor to define a root section, a ramp portion inclined upwardly and outwardly from said root section to a sharp crest, and an engagement face extending from said crest to said channel floor and disposed substantially perpendicularly thereto,   a pawl integrally hinged to said head in said head opening for engaging and gripping said strap, said pawl having a plurality of transversely extending pawl teeth each having a shape complementary to the shape of said rack teeth,   said integrally merged portions of said rack teeth root sections and said channel floor defining a plurality of stress lines extending transversely across said channel between said side rails, said strap having its minimum material thickness substantially coincident with said transverse stress lines,   and at least one longitudinally extending bead disposed in said channel between and substantially parallel to said side rails, said bead being formed integrally with said channel floor and having a generally rounded outer surface,   said bead integrally connecting and longitudinally tying said rack teeth successively together from said engagement face of one rack tooth to said ramp portion of the next adjacent tooth,   and said bead forming an elongation of said transverse stress lines and a diversion of said stress lines in a non-linear direction up and over said rounded outer surface thereof to thereby increase the fracture resistance of said strap adjacent said rack teeth root sections where said strap has its minimum material thickness.   
     
     
       2. A cable tie as defined in claim 1 wherein said bead increases the material thickness of said strap in said channel floor along said transverse stress lines. 
     
     
       3. A cable tie as defined in claim 1, wherein said bead has a height less than the height of said crests of said rack teeth. 
     
     
       4. A cable tie as defined in claim 1, wherein at least one of said beads is substantially centered in said channel. 
     
     
       5. A cable tie as defined in claim 1, including a plurality of said beads disposed in said channel. 
     
     
       6. A cable tie as defined in claim 5 wherein said beads are substantially semi-cylindrical in shape and have a height less than the height of said crests of said rack teeth. 
     
     
       7. A cable tie as defined in claim 5, wherein said beads are disposed in said channel in substantially equally spaced-apart relation to said side rails. 
     
     
       8. A cable tie as defined in claim 1, wherein said beads include at least one bead disposed in said channel in spaced-apart relation to said side rails and a pair of partial beads disposed in said channel and merging integrally into said side rails. 
     
     
       9. A cable tie as defined in claim 1, wherein said bead is substantially semi-cylindrical in shape. 
     
     
       10. A cable tie as defined in claim 1, wherein said channel floor between said rack teeth root sections and engagement faces is formed with generally rounded concave depressions extending laterally from each side of said bead toward said side rails. 
     
     
       11. A cable tie as defined in claim 10, including a plurality of beads disposed in said channel and said concave depressions between said beads extend substantially from the side of one bead to the side of the adjacent bead. 
     
     
       12. A cable tie as defined in claim 11, wherein said transverse stress lines substantially bisect said concave depressions and said stress lines have a substantially sinusoidal shape. 
     
     
       13. A cable tie as defined in claim 10 wherein the height of said bead is substantially less than the height of said rack teeth crests and the depth of said concave depressions is substantially equal to the height of said bead. 
     
     
       14. A cable tie as defined in claim 10 wherein said bead increases the material cross-sectional area of said strap in said channel floor along said transverse stress lines by an amount that is equal to or greater than the decrease in material cross-sectional area of said strap created by said concave depressions along said transverse stress lines. 
     
     
       15. A cable tie comprising a head portion and an elongated flexible strap portion, said head portion having an opening housing an integrally hinged pawl formed with a plurality of transversely extending pawl teeth,   said strap portion being formed with a longitudinally extending channel therein, said channel having a floor defining a rack with a plurality of longitudinally spaced, transversely extending rack teeth,   said pawl teeth and said rack teeth having complimentary shapes and being adapted to engage and grip one another when said strap is inserted into said head portion opening,   said rack teeth having root sections integrally merging into said channel, crest portions projecting upwardly and outwardly therefrom, and generally perpendicular engagement surfaces interconnecting the crest portion of one rack tooth with the channel floor adjacent the root section of the next successive adjacent rack tooth,   and at least one elongated bead extending longitudinally in and integrally formed in said channel floor so as to connect said rack teeth together, said bead having a generally rounded outer surface and a height less than the height of said tooth crests so that the transverse edges of said crests are uninterrupted.   
     
     
       16. A cable tie as defined in claim 15 wherein said pawl teeth have root sections integrally merging into said pawl, sharp crest portions projecting outwardly therefrom, and generally perpendicular engagement surfaces interconnecting the crest portion of one pawl tooth with the pawl adjacent the root section of the next successive pawl tooth, said sharp crest portions of said pawl teeth defining substantially linear transversely extending edges prior to gripping engagement with said rack teeth, and said transversely extending edges of said pawl teeth being deformable to conform generally to the contour of said rounded outer surface of said bead when said pawl teeth are pulled into firm gripping engagement with said rack teeth. 
     
     
       17. A cable tie as defined in claim 16 including a plurality of said beads disposed in said channel in substantially equally spaced-apart relation to one another. 
     
     
       18. A cable tie as defined in claim 15, wherein said channel floor between said rack teeth root sections and engagement faces is formed with generally rounded concave depressions extending laterally from each side of said bead. 
     
     
       19. A cable tie as defined in claim 18, including a plurality of beads disposed in said channel and said concave depressions between said beads extend substantially from the side of one bead to the side of the adjacent bead. 
     
     
       20. A cable tie as defined in claim 19, wherein the depth of said concave depressions is substantially equal to the height of said bead.